The present invention relates generally to passive remote control devices, portable remotely powered communication devices, and communication devices that employ electrostatic or electromagnetic coupling. More particularly, the invention relates to radio frequency identification (RFID) units in combination with a remote control system.
Remotely powered electronic devices and related systems for supplying power to and receiving stored information from such devices are known. For example, U.S. Pat. No. 5,009,227 issued to Geiszler et al., titled refer Proximity xe2x80x9cDetecting Apparatusxe2x80x9d, discloses a remotely powered device that uses electromagnetic coupling to derive power from a remote source and then uses both electromagnetic and electrostatic coupling to transmit stored data to a receiver often collocated with the remote source. These systems are also known as radio frequency identification (xe2x80x9cRFIDxe2x80x9d) systems. Such RFID systems are usable in numerous applications, including, for example, in inventory control, livestock control, and sentry systems. Additionally, radio frequency identification tags are used in electronic article surveillance (xe2x80x9cEASxe2x80x9d) systems, such as those used at exits in retail establishments where merchandise is sold.
Typically, RFID systems are limited to applications for identification and tracking of persons or things. This limitation is due in part to the power, space and cost associated with adding a complex control application to an RFID tag. Generally, RFID tags and systems are optimized to reduce the size, power and cost requirements for the RFID tag. Unfortunately, this optimization tends to limit the ability to apply traditional techniques (e.g., adding circuitry) to expand functions on an RFID tag. Therefore, novel techniques are required to efficiently add control functions to an RFID tag without adversely affecting the size cost and power requirements.
Remote control devices are also known. Remote control devices are used for more complex control operations, for example, to remotely control all types of electronic devices and appliances, including televisions, videocassette recorders, cameras and a plethora of other devices. Remote control devices commonly use infrared or radio frequency wireless data transmission. Typically these remote control devices have an integrated power source such as batteries. The integrated power source removes some of the limitations associated with adding control in a remotely powered RFID system.
One problem with traditional remote control devices is the requirement of an integrated or wired power source such as a battery. As is universally known, batteries do not last forever and their certain but untimely demise is a continuing source of inconvenience and frustration. Another problem, at least with infrared remote control devices, is the requirement that there be a line of sight between the remote control device and the device being controlled, i.e., the controlled device. Not only is this a problem from the perspective of using the remote control device, but this also limits the location of the infrared receiver in the controlled device.
Therefore, a need exists for a remote control device that is capable of complex control operations, but does not require a direct power source such as a battery and requires no line of sight for operation.